Behavior of charge-exchanged deuterium flux and the relation to evacuated tritium in degassing discharges on JT-60U

Abstract Change-over experiments using hydrogen and helium were carried out after deuterium operations in JT-60U. We measured the behavior of charge-exchanged deuterium flux with a neutral particle energy (CX) analyzer and the amount of evacuated tritium with a tritium monitor system. By analyzing the time evolution and shot sequence of the deuterium flux, effective plasma operations for rapid depletion of hydrogen isotopes are obtained. The deuterium flux behavior in the range of days was correlated with the evacuated tritium.